Mr. Zheng Ruiting proposed the following ways:
Electrolysis: Sand castings phosphoric acid (density = 1.7g/cm3) 3000mL water 1500mL, sulfuric acid 1000mL, at room temperature, was back piece as the anode, current density 3 ~ 5A/dm2, electrolytic stripping. This method is easy to produce, after a net withdrawal replacement of copper, nickel should be finished in the back and then back in dilute chromic acid solution of copper.
Chemical stripping method can be applied:
Method of a potassium pyrophosphate 150g / L, room temperature soak.
Method Two: ferric chloride Aluminum castings 750 ~ 810g / L, room temperature soak.